Aircraft structure



July 11, '1939. A. P. DEISEVER.SKY 2,165,459

AIRCRAFT STRUCTURE Filed March 5, 1938 l W W versky HIS ATTORNEY.

Patented July 11, 1939 UNITED STATES PATENT OFFICE AIRCRAFT STRUCTURE Alexander P. de Seversky, Northport, N. Y., assignor to Seversky Aircraft Corporation, a corporation of Delaware This invention, relates to aircraft construction and particularly to the covering, or skin, for the various frameworks of aircraft.

It is especially directed towards improving the mode of attachment of fabric, or textile, coverings to these frameworks, but, as will be made manifest, is equally well adapted to improving the mode of attachment of other sheet material to the framework parts of airplanes.

A particular object of the invention is to provide an attachment of fabric to the frameworks of aircraft whereby to obviate stitching, lacing, or the other modes of attachment 'of the kind which cause a series of protrusions, corrugations, etc., to appear on the surface of the airplane skin, thereby setting up detrimental skin-friction effects and other undesirable aerodynamic phenomena, and instead to provide a substantially smooth, flush skin, or covering, for the framework.

Another particular object of the invention is to provide a mode of attaching the skin to airplane frameworks such that the skin, though the attachment will be quite rigid and firm, may be simply and quickly removed from, as well as secured to, the framework.

The other objects and advantages of the invention will be made manifest as this disclosure progresses. l

The inventive concept will be illustrated, by way of example only, in connection with the attachment of fabric to the metallic framework of a rudder, but it is to be understood that the fabric can just as well be applied, in accordance with the invention, to other parts of the airplane than rudders, and to wooden frameworks. In the drawing,

Figure 1 is a side elevation, partly broken away, of a rudder with fabric attached thereto by means of the present invention;

Figure 2 is an enlarged, fragmentary perspective sectional detail on line 2--2 of Figure 1, and

Figure 3' is an enlarged, fragmentary plan of the construction of the present invention.

In the construction shown in the drawing, the rudder, or other structural frame, is provided with cap strips, I, for its ribs (not shown, but underlying the cap strips). The cap strips are here shown as metal channels, for fitting over the tops of metal ribs, but the invention may equally well be applied to wooden cap strips fitting over wooden ribs. In either case, the cap strips are provided with a groove, or V-depression, 2. The fabric sheet entirely encloses, and stretches tautly over the framework, contacting the upper edges of the V, and the sheet is united at its meeting edges in any suitable manner. It is doped and painted in this taut condition, and, when dry, stringers 3, here shown as thin metallic strips with a V cross section, that is, having their bottom surfaces congruent with the slope and shape of the bottom part of the V in the cap strips, are wedged, or otherwise forced into thegroove against the fabric, thus drawing the taut fabric still tauter. The wedging of the stringers 3 into the cap strip temporarily holds the fabric in place, and, while in place, holes 4 are drilled through the stringers, fabric, and cap strip, and

if desired, the rib underneath, at rather close intervals.

All the parts are attached together and to the rib by self-tapping screws 5, preferably with heads of the countersunk type with a slope which fits congruently into the V of the stringers, leaving the head well below the surface of the covering.

In wooden-framework structures, the stringers may consist of wooden strips with a hollow, V cross-section, or of solid triangular strips. In this case, the cap strips being of wood also, for cooperation with wooden ribs, standard wood screws are employed.

In either case, a length of fabric seam-tape 6, of the proper width, is attached, preferably with a well-known airplane dope, to the outer surface of the fabric over the depression, leaving all the outer faces of the rudder, or other structural frame of the airplane, substantially uninterrupted, smooth, flush surface.

In order to remove the fabric, it is only necessary to loosen the strips 6, as with a suitable sol vent, such as acetone, remove same, and remove the screws 5. The single seam where the two ends of the unitary sheet or bag of fabric are joined can be easily opened in a suitable manner, and the fabric slipped off the framework as a unit.

Having now' disclosed my invention in such manner as to enable those skilled in the art to make and use same, what I claim as my property,

and desire to secure by Letters Patent of the United States, is:

Aircraft structure comprising Dre-fabricated M shaped frame members united to form a hollow overall-framework, the top of the M being sprung together to impart a laterally comprestape over the outside of the said structures.

ALEXANDER P. DE SEVERSKY. 

